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Sokoloff M, Feldman KW, Levin AV, Rockter A, Armijo-Garcia V, Musick M, Weeks K, Haney SB, Marinello M, Herman BE, Frazier TN, Carroll CL, Hymel KP. Retinal hemorrhage variation in inertial versus contact head injuries. CHILD ABUSE & NEGLECT 2024; 149:106606. [PMID: 38134727 DOI: 10.1016/j.chiabu.2023.106606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 12/07/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023]
Abstract
BACKGROUND Abusive head trauma (AHT) is frequently accompanied by dense/extensive retinal hemorrhages to the periphery with or without retinoschisis (complex retinal hemorrhages, cRH). cRH are uncommon without AHT or major trauma. OBJECTIVE The study objectives were to determine whether cRH are associated with inertial vs. contact mechanisms and are primary vs. secondary injuries. PARTICIPANTS AND SETTING This retrospective study utilized a de-identified PediBIRN database of 701 children <3-years-old presenting to intensive care for head trauma. Children with motor vehicle related trauma and preexisting brain abnormalities were excluded. All had imaging showing head injury and a dedicated ophthalmology examination. METHODS Contact injuries included craniofacial soft tissue injuries, skull fractures and epidural hematoma. Inertial injuries included acute impairment or loss of consciousness and/or bilateral and/or interhemispheric subdural hemorrhage. Abuse was defined in two ways, by 1) predetermined criteria and 2) caretaking physicians/multidisciplinary team's diagnostic consensus. RESULTS PediBIRN subjects with cRH frequently experienced inertial injury (99.4 % (308/310, OR = 53.74 (16.91-170.77)) but infrequently isolated contact trauma (0.6 % (2/310), OR = 0.02 (0.0004-0.06)). Inertial injuries predominated over contact trauma among children with cRH sorted AHT by predetermined criteria (99.1 % (237/239), OR = 20.20 (6.09-67.01) vs 0.5 % (2/339), OR = 0.04 (0.01-0.17)). Fifty-nine percent of patients with cRH, <24 h altered consciousness, and inertial injuries lacked imaging evidence of brain hypoxia, ischemia, or swelling. CONCLUSIONS cRH are significantly associated with inertial angular acceleration forces. They can occur without brain hypoxia, ischemia or swelling suggesting they are not secondary injuries.
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Affiliation(s)
- Michael Sokoloff
- Department of Pediatrics, Pediatric Intensive Care, Sacred Heart Children's Hospital, Spokane, WA, United States of America.
| | - Kenneth W Feldman
- Department of Pediatrics, Seattle Children's, University of Washington's Harborview Medical Center, Seattle, WA, United States of America; Department of Pediatrics, Safe Child and Adolescent Network, Seattle Children's, Seattle, WA, United States of America.
| | - Alex V Levin
- Department of Ophthalmology, Flaum Eye Institute, University of Rochester, Rochester, NY, United States of America.
| | - Adam Rockter
- University of Rochester School of Medicine, Rochester, NY, United States of America.
| | - Veronica Armijo-Garcia
- Department of Pediatrics, University of Texas Health Sciences Center at San Antonio, San Antonio, TX, United States of America.
| | - Matthew Musick
- Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, United States of America.
| | - Kerri Weeks
- Department of Pediatrics, University of Kansas School of Medicine, Wichita, KS, United States of America.
| | - Suzanne B Haney
- Department of Pediatrics, University of Nebraska Medical Center, Children's Hospital and Medical Center, Omaha, NE, United States of America.
| | - Mark Marinello
- Department of Pediatrics, Children's Hospital of Richmond at VCU, Richmond, VA, United States of America.
| | - Bruce E Herman
- Department of Pediatrics, University of Utah School of Medicine, Primary Children's Hospital, Salt Lake City, UT, United States of America.
| | - Terra N Frazier
- Department of Pediatrics, Children's Mercy Hospital, Kansas City, MO, United States of America.
| | - Christopher L Carroll
- Department of Pediatrics, Connecticut Children's Medical Center, Hartford, CT, United States of America.
| | - Kent P Hymel
- Department of Pediatrics, Penn State College of Medicine, Hershey, PA, United States of America
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2
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Zengin S, Mercan S, Tarhan D, Gök A, Ercan AM. Age-related changes on physicochemical properties of the artificial vitreous humor: A practical tool for enhancing ex vivo studies. Exp Eye Res 2024; 239:109762. [PMID: 38147936 DOI: 10.1016/j.exer.2023.109762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/01/2023] [Accepted: 12/20/2023] [Indexed: 12/28/2023]
Abstract
The vitreous humor (VH) is a hydrophilic, jelly-like ocular fluid, which is located in the posterior chamber of the eye. The rheological, structural, and chemical properties of VH change significantly during aging, which further causes eye-associated diseases and could be a potential indicator for various diseases. In this study, artificial VH (A-VH) samples were created by taking into account different age groups to observe age-related changes in the physicochemical properties of these samples. This study aimed to measure the physicochemical properties of age-dependently prepared A-VH samples to determine the changes with aging in the physicochemical properties of A-VH samples. Phosphate-buffered saline (PBS)-based A-VH samples were prepared in three types representing adult, middle-aged, and elder individuals. Age-related changes in physicochemical properties (surface tension, osmolality, pH, relative viscosity, density, and refractive index) were analyzed by related equipment. The A-VH samples, prepared using PBS, showed strong similarity to authentic VH in terms of physicochemical properties. While the age-related changes studies have revealed some discrepancies between age-dependently prepared A-VH samples in terms of surface tension, osmolality, relative viscosity, and pH with high correlation coefficients (r2 > 0,94), density and refractive index values did not show any significant differences and correlation between types of A-VH representing 3 age groups. In conclusion, age-dependent A-VH samples were created successfully to use ex vivo method development studies, and the influence of aging on the physicochemical properties of VH was demonstrated as well.
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Affiliation(s)
- Simge Zengin
- Istanbul University-Cerrahpaşa, Institute of Forensic Sciences and Legal Medicine, Department of Science, Buyukcekmece, Istanbul, Turkey
| | - Selda Mercan
- Istanbul University-Cerrahpaşa, Institute of Forensic Sciences and Legal Medicine, Department of Science, Buyukcekmece, Istanbul, Turkey.
| | - Duygu Tarhan
- Bahcesehir University, School of Medicine, Department of Biophysics, Goztepe, Istanbul, Turkey
| | - Aslı Gök
- Istanbul University-Cerrahpaşa, Faculty of Engineering, Department of Chemical Engineering, Avcılar, Istanbul, Turkey
| | - Alev Meltem Ercan
- Istanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, Department of Biophysics, Fatih, Istanbul, Turkey
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3
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Kumar N, Bazgain K, Singh SR, Katoch D. Sodium fluorescein dye as an adjunct in vitrectomy for rhegmatogenous retinal detachment in oculocutaneous albinism. Oman J Ophthalmol 2024; 17:124-126. [PMID: 38524338 PMCID: PMC10957032 DOI: 10.4103/ojo.ojo_35_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/20/2023] [Accepted: 09/23/2023] [Indexed: 03/26/2024] Open
Abstract
A 48-year-old male with oculocutaneous albinism (OCA) presented with bilateral diminution of vision. Ocular examination revealed bilateral central corneal thinning, scarring with ectasia, depigmented irides, transillumination defects, and pseudophakia. Examination of the right eye also revealed a hyperoleon, emulsified silicon oil in the vitreous cavity, and an attached retina, while the left eye had a total rhegmatogenous retinal detachment (RRD). This case describes a unique set of challenges (the presence of an ectatic scarred cornea and a hypopigmented fundus) and sodium fluorescein dye as an adjunct in the surgical management of a complex RRD. A review of literature highlighting the association of keratoconus and RRD in OCA is also presented in this report.
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Affiliation(s)
- Nitin Kumar
- Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Krinjeela Bazgain
- Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Simar Rajan Singh
- Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Deeksha Katoch
- Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
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Luo RH, Tram NK, Parekh AM, Puri R, Reilly MA, Swindle-Reilly KE. The Roles of Vitreous Biomechanics in Ocular Disease, Biomolecule Transport, and Pharmacokinetics. Curr Eye Res 2023; 48:195-207. [PMID: 35179421 DOI: 10.1080/02713683.2022.2033271] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE The biomechanical properties of the vitreous humor and replication of these properties to develop substitutes for the vitreous humor have rapidly become topics of interest over the last two decades. In particular, the behavior of the vitreous humor as a viscoelastic tissue has been investigated to identify its role in a variety of processes related to biotransport, aging, and age-related pathologies of the vitreoretinal interface. METHODS A thorough search and review of peer-reviewed publications discussing the biomechanical properties of the vitreous humor in both human and animal specimens was conducted. Findings on the effects of biomechanics on vitreoretinal pathologies and vitreous biotransport were analyzed and discussed. RESULTS The pig and rabbit vitreous have been found to be most mechanically similar to the human vitreous. Age-related liquefaction of the vitreous creates two mechanically unique phases, with an overall effect of softening the vitreous. However, the techniques used to acquire this mechanical data are limited by the in vitro testing methods used, and the vitreous humor has been hypothesized to behave differently in vivo due in part to its swelling properties. The impact of liquefaction and subsequent detachment of the vitreous humor from the posterior retinal surface is implicated in a variety of tractional pathologies of the retina and macula. Liquefaction also causes significant changes in the biotransport properties of the eye, allowing for significantly faster movement of molecules compared to the healthy vitreous. Recent developments in computational and ex vivo models of the vitreous humor have helped with understanding its behavior and developing materials capable of replacing it. CONCLUSIONS A better understanding of the biomechanical properties of the vitreous humor and how these relate to its structure will potentially aid in improving clinical metrics for vitreous liquefaction, design of biomimetic vitreous substitutes, and predicting pharmacokinetics for intravitreal drug delivery.
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Affiliation(s)
- Richard H Luo
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Nguyen K Tram
- Center for Regenerative Medicine, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Ankur M Parekh
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
| | - Raima Puri
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Matthew A Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, USA
| | - Katelyn E Swindle-Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, USA
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Chen R, Folio D, Ferreira A. Optimal Design of a Multipole-Electromagnet Robotic Platform for Ophthalmic Surgery. MICROMACHINES 2022; 14:91. [PMID: 36677152 PMCID: PMC9865419 DOI: 10.3390/mi14010091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/16/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
The aim of this study was to design a multipole-electromagnet robotic platform named OctoRob. This platform provides a minimally invasive means for targeted therapeutic interventions in specific intraocular areas. OctoRob is capable of generating both appropriate magnetic fields and gradients. The main scientific objectives were: (i) To propose an optimal reconfigurable arrangement of electromagnets suitable for ophthalmic interventions. (ii) To model, design and implement a one-degree-of-freedom robotic arm connected with an electromagnet in order to optimize the generation of magnetic fields and gradients. (iii) To evaluate the magnetic performances of the OctoRob platform, including different tilted angles. The results show that OctoRob platform has great potential to be applied for ophthalmic surgery.
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Affiliation(s)
| | - David Folio
- Correspondence: (D.F.); (A.F.); Tel.: +33-(0)2-48-48-40-75 (D.F.); +33-(0)2-48-48-40-79 (A.F.)
| | - Antoine Ferreira
- Correspondence: (D.F.); (A.F.); Tel.: +33-(0)2-48-48-40-75 (D.F.); +33-(0)2-48-48-40-79 (A.F.)
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6
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Phillips JD, Hwang ES, Morgan DJ, Creveling CJ, Coats B. Structure and mechanics of the vitreoretinal interface. J Mech Behav Biomed Mater 2022; 134:105399. [PMID: 35963021 PMCID: PMC9552593 DOI: 10.1016/j.jmbbm.2022.105399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 07/17/2022] [Accepted: 07/24/2022] [Indexed: 12/24/2022]
Abstract
Vitreoretinal mechanics plays an important role in retinal trauma and many sight-threatening diseases. In age-related pathologies, such as posterior vitreous detachment and vitreomacular traction, lingering vitreoretinal adhesions can lead to macular holes, epiretinal membranes, retinal tears and detachment. In age-related macular degeneration, vitreoretinal traction has been implicated in the acceleration of the disease due to the stimulation of vascular growth factors. Despite this strong mechanobiological influence on trauma and disease in the eye, fundamental understanding of the mechanics at the vitreoretinal interface is limited. Clarification of adhesion mechanisms and the role of vitreoretinal mechanics in healthy eyes and disease is necessary to develop innovative treatments for these pathologies. In this review, we evaluate the existing literature on the structure and function of the vitreoretinal interface to gain insight into age- and region-dependent mechanisms of vitreoretinal adhesion. We explore the role of vitreoretinal adhesion in ocular pathologies to identify knowledge gaps and future research areas. Finally, we recommend future mechanics-based studies to address the critical needs in the field, increase fundamental understanding of vitreoretinal mechanisms and disease, and inform disease treatments.
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Affiliation(s)
- Joseph D Phillips
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Eileen S Hwang
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, United States
| | - Denise J Morgan
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, United States
| | | | - Brittany Coats
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, United States.
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7
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Song HH, Thoreson WB, Dong P, Shokrollahi Y, Gu L, Suh DW. Exploring the Vitreoretinal Interface: a Key Instigator of Unique Retinal Hemorrhage Patterns in Pediatric Head Trauma. KOREAN JOURNAL OF OPHTHALMOLOGY 2022; 36:253-263. [PMID: 35527527 PMCID: PMC9194735 DOI: 10.3341/kjo.2021.0133] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 02/18/2022] [Indexed: 11/25/2022] Open
Abstract
Purpose Various types of trauma can cause retinal hemorrhages in children, including accidental and nonaccidental head trauma. We used animal eyes and a finite element model of the eye to examine stress patterns produced during purely linear and angular accelerations, along with stresses attained during simulated repetitive shaking of an infant. Methods Using sheep and primate eyes, sclerotomy windows were created by removing the sclera, choroid, and retinal pigment epithelium to expose the retina. A nanofiber square was glued to a 5 mm2 area of retina. The square was pulled and separated from vitreous while force was measured. A finite element model of the pediatric eye was used to computationally measure tension stresses during shaking. Results In both sheep and primate eyes, tension stress required for separation of retina from vitreous range from 1 to 5 kPa. Tension stress generated at the vitreoretinal interface predicted by the computer simulation ranged from 3 to 16 kPa during a cycle of shaking. Linear acceleration generated lower tension stress than angular acceleration. Angular acceleration generated maximal tension stress along the retinal vasculature. Linear acceleration produced more diffuse force distribution centered at the poster pole. Conclusions The finite element model predicted that tension stress attained at the retina during forcible shaking of an eye can exceed the minimum threshold needed to produce vitreoretinal separation as measured in animal eyes. Furthermore, the results show that movements that involve significant angular acceleration produce strong stresses localized along the vasculature, whereas linear acceleration produces weaker, more diffuse stress centered towards the posterior pole of the eye.
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Affiliation(s)
- Helen H Song
- University of Nebraska Medical Center, Truhlsen Eye Institute, Omaha, NE
| | - Wallace B Thoreson
- University of Nebraska Medical Center, Truhlsen Eye Institute, Omaha, NE
| | - Pengfei Dong
- Florida Institute of Technology, Department of Biomedical & Chemical Engineering, Melbourne, FL
| | - Yasin Shokrollahi
- Florida Institute of Technology, Department of Biomedical & Chemical Engineering, Melbourne, FL
| | - Linxia Gu
- Florida Institute of Technology, Department of Biomedical & Chemical Engineering, Melbourne, FL
| | - Donny W Suh
- University of Nebraska Medical Center, Truhlsen Eye Institute, Omaha, NE.,Children's Hospital and Medical Center, Omaha, NE
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8
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Magonio F. REM phase: An ingenious mechanism to enhance clearance of metabolic waste from the retina. Exp Eye Res 2021; 214:108860. [PMID: 34843744 DOI: 10.1016/j.exer.2021.108860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/03/2021] [Accepted: 11/17/2021] [Indexed: 11/04/2022]
Abstract
The Rapid Eye Movement (REM) phase of sleep, also known as "active sleep" because of physiological similarities to waking state, is characterized by intense cerebral electrical activity, propensity to dream vividly and suppression of skeletal muscle activity (atonia) except for the extraocular muscles which give rise to the so-called REM. In 1998 David Maurice, an ophthalmologist, proposed that REM sleep was associated with an eye function: it would be required to stir the anterior chamber and bath it with aqueous humor to prevent corneal anoxia during sleep. However, potential metabolic problems could arise in the outer retinal layers which lack a direct blood supply. New research lends support to the hypothesis that a para-vascular transport system, the so-called "glymphatic", is present in the eye analogous to the one recently discovered in the brain. It is a functional waste clearance pathway which promotes elimination of interstitial solutes from the brain along para-vascular channels. Glymphatic function increases during sleep and just as a "brain pump" moves fluids in the central nervous system, a "vitreous pump" moves them into the eyeballs during REM phase. A number of similarities between Alzheimer's disease and several retinal degenerations have been described, particularly with respect to either age-related macular degeneration and chronic open-angle glaucoma. Impairment of this mechanism in some disease states and in the normal aging process could have serious consequences for visual function. In this manuscript I propose a new hypothesis regarding the role of REM phase on physio-pathology of the human eye: it would be an ingenious mechanism to enhanced clearance of metabolic waste from the retina.
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Affiliation(s)
- Fabrizio Magonio
- Igea Private Hospital, Department of Ophthalmology, Via Marcona, 69, 20129, Milano, Italy.
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9
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Wang R, Snead M, Alexander P, Ian Wilson D. Assessing bulk emulsification at the silicone oil - saline solution interface in a 3D model of the eye. Acta Ophthalmol 2021; 99:e209-e214. [PMID: 32701223 DOI: 10.1111/aos.14539] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/28/2020] [Accepted: 06/13/2020] [Indexed: 11/27/2022]
Abstract
PURPOSE Emulsification of silicone oil (SiOil) in a vitrectomized eye was investigated using a 3D model of the vitreous cavity to test the hypothesis that oil droplet formation arises from the breakdown of the bulk SiOil-aqueous interface during eye saccadic movement. METHODS Round bottom flasks filled with SiOil and a saline phase modelled the vitrectomized SiOil-filled eye. A stepper motor imposed saccadic movements and the oil/aqueous interface was monitored with digital cameras. A range of SiOil viscosities, flask diameters, motion scenarios and levels of fill were studied. Estimates of velocity profiles in the fluid on the equatorial plane of a sphere subject to saccadic motion were obtained from an analytical solution to the Navier-Stokes equations. RESULTS Interfacial waves were observed at saccadic motions with higher acceleration, amplitude and frequency. Low interfacial tension between the two fluids, lower oil viscosity and smaller level of SiOil fill all promoted large deformations of the interface. No droplets were formed at the bulk SiOil-aqueous interface. However, formation and detachment of oil droplets were observed at the three-phase contact line under certain conditions. CONCLUSIONS The stresses generated at the liquid-liquid interface are not large enough to form droplets in the bulk region for conditions representative of these in the eye. Bulk emulsification of the SiOil, reported as the main formation mechanism by some workers, is not responsible for droplet formation in a vitrectomized SiOil-filled eye set-up. This result confirms recent finding on droplet formation driven by a surface emulsification mechanism.
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Affiliation(s)
- Ru Wang
- Department of Chemical Engineering and Biotechnology University of Cambridge Cambridge UK
| | - Martin Snead
- Addenbrooke's Hospital Cambridge University Hospitals NHS Foundation Trust Cambridge UK
| | - Philip Alexander
- Addenbrooke's Hospital Cambridge University Hospitals NHS Foundation Trust Cambridge UK
| | - D. Ian Wilson
- Department of Chemical Engineering and Biotechnology University of Cambridge Cambridge UK
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10
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Suh DW, Song HH, Mozafari H, Thoreson WB. Determining the Tractional Forces on Vitreoretinal Interface Using a Computer Simulation Model in Abusive Head Trauma. Am J Ophthalmol 2021; 223:396-404. [PMID: 32663454 DOI: 10.1016/j.ajo.2020.06.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 06/13/2020] [Accepted: 06/16/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE Abusive head trauma (AHT) is the leading cause of infant death and long-term morbidity from injury. The ocular consequences of AHT are controversial, and the pathophysiology of retinal research findings is still not clearly understood. It has been postulated that vitreoretinal traction plays a major role in the retinal findings. A computer simulation model was developed to evaluate the vitreoretinal traction and determine whether the distribution of forces in different layers and locations of the retina can explain the patterns of retinal hemorrhage (RH) seen in AHT. DESIGN Computer simulation model study. METHODS A computer simulation model of the pediatric eye was developed to evaluate preretinal, intraretinal, and subretinal stresses during repetitive shaking. This model was also used to examine the forces applied to various segments along blood vessels. RESULTS Calculated stress values from the computer simulation ranged from 3-16 kPa at the vitreoretinal interface through a cycle of shaking. Maximal stress was observed at the periphery of the retina, corresponding to areas of multiple vessel bifurcations, followed by the posterior pole of the retina. Stress values were similar throughout all 3 layers of the retina (preretinal, intraretinal, and subretinal layers). CONCLUSIONS Ocular manifestations from AHT revealed unique retinal characteristics. The model predicted stress patterns consistent with the diffuse retinal hemorrhages (RH) typically found in the posterior pole and around the peripheral retina in AHT. This computer model demonstrated that similar stress forces were produced in different layers of the retina, consistent with the finding that retinal hemorrhages are often found in multiple layers of the retina. These data can help explain the RH patterns commonly found in AHT.
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11
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Bayat J, Emdad H, Abouali O. 3D numerical investigation of the fluid mechanics in a partially liquefied vitreous humor due to saccadic eye movement. Comput Biol Med 2020; 125:103955. [DOI: 10.1016/j.compbiomed.2020.103955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 07/31/2020] [Accepted: 07/31/2020] [Indexed: 10/23/2022]
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12
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Silva AF, Pimenta F, Alves MA, Oliveira MSN. Flow dynamics of vitreous humour during saccadic eye movements. J Mech Behav Biomed Mater 2020; 110:103860. [PMID: 32755799 DOI: 10.1016/j.jmbbm.2020.103860] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/20/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Abstract
In this work, we reveal the flow dynamics of Vitreous Humour (VH) gel and liquid phases during saccadic movements of the eye, considering the biofluids viscoelastic character as well as realistic eye chamber geometry and taking into account the saccade profile. We quantify the differences in the flow dynamics of VH gel and liquid phases using viscoelastic rheological models that are able to model the VH shear rheology, considering different amplitudes of saccadic movements (10∘, 20∘, 30∘ and 40∘). For this purpose, the computational fluid dynamics (CFD) open source software OpenFOAM® was used. The results portray a distinct flow behaviour for the VH gel and liquid phases, with inertial effects being more significant for the VH liquid phase. Moreover, the Wall Shear Stress (WSS) values produced by the VH gel phase are more than twice of those generated by the VH liquid phase. Results also show that for different amplitudes of eye movement both the velocity magnitude in the vitreous cavity and the shear stresses on the cavity walls rise with increasing saccadic movement displacement.
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Affiliation(s)
- Andreia F Silva
- James Weir Fluids Laboratory, Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow, G1 1XJ, UK; School of Physics and Astronomy, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JL, UK.
| | - Francisco Pimenta
- Departamento de Engenharia Química, CEFT, Faculdade de Engenharia, Universidade do Porto, 4200-465, Porto, Portugal
| | - Manuel A Alves
- Departamento de Engenharia Química, CEFT, Faculdade de Engenharia, Universidade do Porto, 4200-465, Porto, Portugal
| | - Mónica S N Oliveira
- James Weir Fluids Laboratory, Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow, G1 1XJ, UK
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Di Michele F, Tatone A, Romano MR, Repetto R. A mechanical model of posterior vitreous detachment and generation of vitreoretinal tractions. Biomech Model Mechanobiol 2020; 19:2627-2641. [DOI: 10.1007/s10237-020-01360-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/19/2020] [Indexed: 01/21/2023]
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14
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Thakur SS, Pan X, Kumarasinghe GL, Yin N, Pontré BP, Vaghefi E, Rupenthal ID. Relationship between rheological properties and transverse relaxation time (T2) of artificial and porcine vitreous humour. Exp Eye Res 2020; 194:108006. [DOI: 10.1016/j.exer.2020.108006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/12/2020] [Accepted: 03/13/2020] [Indexed: 12/20/2022]
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15
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Thakur SS, Shenoy SK, Suk JS, Hanes JS, Rupenthal ID. Validation of hyaluronic acid-agar-based hydrogels as vitreous humor mimetics for in vitro drug and particle migration evaluations. Eur J Pharm Biopharm 2020; 148:118-125. [PMID: 31981693 DOI: 10.1016/j.ejpb.2020.01.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/16/2020] [Accepted: 01/19/2020] [Indexed: 12/26/2022]
Abstract
Artificial vitreous humor holds immense potential for use in in vitro intravitreal drug delivery assays. In this study, we investigated rheological properties and drug or nanoparticle migration in hyaluronic acid (HA) - agar based hydrogels and compared these characteristics with bovine vitreous humor. Gel compositions identified in literature containing HA (0.7-5.0 mg/ml) and agar (0.95-4.0 mg/ml) were classified as either high (VH), medium (VM) or low (VL) polymer load. Viscoelastic behavior was evaluated using oscillatory rheology, and migration of differently sized and charged polystyrene nanoparticles (NPs) through the different gels was determined via multiple particle tracking. Comparable rheological behaviour was observed between VL and bovine vitreous. Tracking evaluations revealed that increasing particle size and gel viscosity slowed NP migration. Additionally, 100 nm anionic NPs migrated slower than neutral NPs in VL and VM, while cationic NPs were immobile in all gels. Finally, distribution and clearance of sodium fluorescein was used to model drug mobility through the gels using a custom-built eye model. Flow and angular movement only influenced drug migration in VL and VM, but not VH. Finally, VL and VM demonstrated to have the most similar sodium fluorescein clearance to that of bovine vitreous humor. Together, these evaluations demonstrate that low viscosity HA-agar gels can be used to approximate nanoparticle and drug migration through biological vitreous humor.
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Affiliation(s)
- Sachin S Thakur
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Siddharth K Shenoy
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Jung Soo Suk
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Justin S Hanes
- Center for Nanomedicine, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Pharmacology & Molecular Sciences, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA; Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD 21231, USA
| | - Ilva D Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Friehmann A, Eng UZ, Rubowitz A. Fluid viscosity but not surface tension, determines the tamponade effect of intravitreal fluids in a novel in vitro eye model of retinal detachment. J Mech Behav Biomed Mater 2020; 101:103452. [DOI: 10.1016/j.jmbbm.2019.103452] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 12/31/2022]
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17
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Sapino S, Chirio D, Peira E, Abellán Rubio E, Brunella V, Jadhav SA, Chindamo G, Gallarate M. Ocular Drug Delivery: A Special Focus on the Thermosensitive Approach. NANOMATERIALS 2019; 9:nano9060884. [PMID: 31207951 PMCID: PMC6630567 DOI: 10.3390/nano9060884] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/05/2019] [Accepted: 06/10/2019] [Indexed: 12/16/2022]
Abstract
The bioavailability of ophthalmic therapeutics is reduced because of the presence of physiological barriers whose primary function is to hinder the entry of exogenous agents, therefore also decreasing the bioavailability of locally administered drugs. Consequently, repeated ocular administrations are required. Hence, the development of drug delivery systems that ensure suitable drug concentration for prolonged times in different ocular tissues is certainly of great importance. This objective can be partially achieved using thermosensitive drug delivery systems that, owing to their ability of changing their state in response to temperature variations, from room to body temperature, may increase drug bioavailability. In the case of topical instillation, in situ forming gels increase pre-corneal drug residence time as a consequence of their enhanced adhesion to the corneal surface. Otherwise, in the case of intraocular and periocular, i.e., subconjunctival, retrobulbar, peribulbar administration, among others, they have the undoubted advantage of being easily injectable and, owing to their sudden thickening at body temperature, have the ability to form an in situ drug reservoir. As a result, the frequency of administration can be reduced, also favoring the patient’s adhesion to therapy. In the main section of this review, we discuss some of the most common treatment options for ocular diseases, with a special focus on posterior segment treatments, and summarize the most recent improvement deriving from thermosensitive drug delivery strategies. Aside from this, an additional section describes the most widespread in vitro models employed to evaluate the functionality of novel ophthalmic drug delivery systems.
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Affiliation(s)
- Simona Sapino
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy.
- NIS Research Centre, University of Turin, 10125 Turin, Italy.
| | - Daniela Chirio
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy.
- NIS Research Centre, University of Turin, 10125 Turin, Italy.
| | - Elena Peira
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy.
- NIS Research Centre, University of Turin, 10125 Turin, Italy.
| | | | - Valentina Brunella
- NIS Research Centre, University of Turin, 10125 Turin, Italy.
- Department of Chemistry, University of Turin, 10125 Turin, Italy.
| | - Sushilkumar A Jadhav
- NIS Research Centre, University of Turin, 10125 Turin, Italy.
- School of Nanoscience and Technology, Shivaji University Kolhapur, Maharashtra 416004, India.
| | - Giulia Chindamo
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy.
| | - Marina Gallarate
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy.
- NIS Research Centre, University of Turin, 10125 Turin, Italy.
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Romano MR, Stocchino A, Ferrara M, Lagazzo A, Repetto R. Fluidics of Single and Double Blade Guillotine Vitrectomy Probes in Balanced Salt Solution and Artificial Vitreous. Transl Vis Sci Technol 2018; 7:19. [PMID: 30564508 PMCID: PMC6284468 DOI: 10.1167/tvst.7.6.19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/27/2018] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To assess the fluidics of double-vitreous cutter blade (DB) compared with single-blade (SB) guillotine with 23-, 25-, and 27-gauge vitrectomy probes. To assess flow characteristics and flow rates in viscous and viscoelastic fluids. METHODS We used Particle Image Velocimetry to measure the flow field close to the tip of each cutter probe and we derived kinematic quantities of interest, such as kinetic energy and acceleration. We performed measurements both on a balanced salt solution (BSS) and on a viscoelastic artificial vitreous (AV). RESULTS The flow rate is significantly higher with DB than SB vitrectomy probes, for a given pumping pressure and cutting rate. The fluid flow observed is very different between BSS and AV tests. CONCLUSIONS The DB has more efficient fluidics than SB vitrectomy probe in all tested conditions. Fluid acceleration depends on the cutting frequency, especially in the case of measurements in AV. The flow rate strongly depends on the pressure and it is little affected by the cutting frequency, in a range of clinical interest. The 27-G DB produces flow rates similar to the 23- and 25-G SB, with significantly smaller acceleration. The flow induced in the AV is different from that in BSS and oscillates at different frequencies. TRANSLATIONAL RELEVANCE DB cutters prove to be more efficient in terms of lower acceleration for a given flow rate. The latter is mainly controlled by aspiration pressure and less by cut rates. The influence of vitreous rheology deserves further investigations.
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Affiliation(s)
- Mario Rosario Romano
- Department of Biomedical Sciences, Humanitas University, Rozzano - Milano, Italy
| | - Alessandro Stocchino
- Department of Civil, Chemical and Environmental Engineering, University of Genoa DICCA, Genoa, Italy
| | - Mariantonia Ferrara
- Department of Biomedical Sciences, Humanitas University, Rozzano - Milano, Italy
| | - Alberto Lagazzo
- Department of Civil, Chemical and Environmental Engineering, University of Genoa DICCA, Genoa, Italy
| | - Rodolfo Repetto
- Department of Civil, Chemical and Environmental Engineering, University of Genoa DICCA, Genoa, Italy
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A Combined Approach for the Analysis of Ocular Fluid Dynamics in the Presence of Saccadic Movements. Ann Biomed Eng 2018; 46:2091-2101. [DOI: 10.1007/s10439-018-02110-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/27/2018] [Indexed: 01/04/2023]
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20
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Mansour AM, Chhablani J, Arevalo JF, Wu L, Sharma R, Sinawat S, Sujirakul T, Assi A, Vélez-Vázquez WM, Mansour MA, Kayikcioglu O, Kucukerdonmez C, Kal A. Retinal detachment in albinism. Clin Ophthalmol 2018; 12:651-656. [PMID: 29670325 PMCID: PMC5896647 DOI: 10.2147/opth.s158785] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose To report the visual and anatomic outcomes of albino retinal detachment (ARD) repair. Methods Collaborative retrospective analysis of ARD. Outcome measures were number of surgical interventions, final retinal reattachment, and best corrected visual acuity (BCVA) at last follow-up. Results Seventeen eyes of 16 patients (12 males; mean age =37.8 years) had the following complications at presentation: macula off (14), total (7) or inferior detachment (5), proliferative vitreoretinopathy (5), detectable break (16), lattice (5), horseshoe tears (9), and giant tear or dialysis (4). Mean number of interventions was 1.8 (range =1–5) and included cryopexy (15) with scleral buckle (11), and/or vitrectomy (8). Mean initial BCVA was counting finger (CF) 1 m and at last follow-up (mean 77 months) CF4m with mean improvement of 4.5 lines (early treatment diabetic retinopathy study) (P=0.05). Intraoperative choroidal hemorrhage occurred in three eyes. The retina was finally attached in 14 eyes, with residual inferior detachment in three eyes with silicone oil in situ. Silicone oil was kept in six of seven eyes because of residual inferior detachment (3) and removal of silicone oil, which led to redetachment (1) or fear of redetachment (2). Conclusion Repair of ARD may require several interventions, with the need to keep silicone oil in several cases due to nystagmus and reduced melanin pigment.
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Affiliation(s)
- Ahmad M Mansour
- Department of Ophthalmology, American University of Beirut, Beirut, Lebanon.,Department of Ophthalmology, Rafic Hariri University Hospital, Beirut, Lebanon
| | - Jay Chhablani
- L.V. Prasad Eye Institute, Banjara Hills, Hyderabad, India
| | - J Fernando Arevalo
- Department of Ophthalmology, Johns Hopkins Bayview Medical Center, Baltimore, MD, USA.,Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lihteh Wu
- Asociados de Macula Vitreo y Retina de Costa Rica, San José, Costa Rica
| | - Ravi Sharma
- L.V. Prasad Eye Institute, Banjara Hills, Hyderabad, India
| | - Suthasinee Sinawat
- Department of Ophthalmology, Srinagarind Hospital, Khon Kaen University, Khon Kaen, Thailand
| | - Tharikarn Sujirakul
- Department of Ophthalmology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | | | | | - Mohamad A Mansour
- Department of Ophthalmology, American University of Beirut, Beirut, Lebanon
| | | | | | - Ali Kal
- Department of Ophthalmology, Baskent University, Konya, Turkey
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21
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Bertens CJ, Gijs M, van den Biggelaar FJ, Nuijts RM. Topical drug delivery devices: A review. Exp Eye Res 2018; 168:149-160. [DOI: 10.1016/j.exer.2018.01.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 12/08/2017] [Accepted: 01/11/2018] [Indexed: 12/22/2022]
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22
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Aloy MÁ, Adsuara JE, Cerdá-Durán P, Obergaulinger M, Esteve-Taboada JJ, Ferrer-Blasco T, Montés-Micó R. Estimation of the mechanical properties of the eye through the study of its vibrational modes. PLoS One 2017; 12:e0183892. [PMID: 28922351 PMCID: PMC5603173 DOI: 10.1371/journal.pone.0183892] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 08/14/2017] [Indexed: 12/28/2022] Open
Abstract
Measuring the eye's mechanical properties in vivo and with minimally invasive techniques can be the key for individualized solutions to a number of eye pathologies. The development of such techniques largely relies on a computational modelling of the eyeball and, it optimally requires the synergic interplay between experimentation and numerical simulation. In Astrophysics and Geophysics the remote measurement of structural properties of the systems of their realm is performed on the basis of (helio-)seismic techniques. As a biomechanical system, the eyeball possesses normal vibrational modes encompassing rich information about its structure and mechanical properties. However, the integral analysis of the eyeball vibrational modes has not been performed yet. Here we develop a new finite difference method to compute both the spheroidal and, specially, the toroidal eigenfrequencies of the human eye. Using this numerical model, we show that the vibrational eigenfrequencies of the human eye fall in the interval 100 Hz-10 MHz. We find that compressible vibrational modes may release a trace on high frequency changes of the intraocular pressure, while incompressible normal modes could be registered analyzing the scattering pattern that the motions of the vitreous humour leave on the retina. Existing contact lenses with embebed devices operating at high sampling frequency could be used to register the microfluctuations of the eyeball shape we obtain. We advance that an inverse problem to obtain the mechanical properties of a given eye (e.g., Young's modulus, Poisson ratio) measuring its normal frequencies is doable. These measurements can be done using non-invasive techniques, opening very interesting perspectives to estimate the mechanical properties of eyes in vivo. Future research might relate various ocular pathologies with anomalies in measured vibrational frequencies of the eye.
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Affiliation(s)
- M. Á. Aloy
- Department of Astronomy and Astrophysics, University of Valencia, 46100 Burjassot, Spain
- * E-mail:
| | - J. E. Adsuara
- Department of Astronomy and Astrophysics, University of Valencia, 46100 Burjassot, Spain
| | - P. Cerdá-Durán
- Department of Astronomy and Astrophysics, University of Valencia, 46100 Burjassot, Spain
| | - M. Obergaulinger
- Department of Astronomy and Astrophysics, University of Valencia, 46100 Burjassot, Spain
| | - J. J. Esteve-Taboada
- Department of Optics and Optometry and Vision Sciences, University of Valencia, 46100 Burjassot, Spain
| | - T. Ferrer-Blasco
- Department of Optics and Optometry and Vision Sciences, University of Valencia, 46100 Burjassot, Spain
| | - R. Montés-Micó
- Department of Optics and Optometry and Vision Sciences, University of Valencia, 46100 Burjassot, Spain
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23
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Sengupta S, Smith DS, Smith AK, Welch EB, Smith SA. Dynamic Imaging of the Eye, Optic Nerve, and Extraocular Muscles With Golden Angle Radial MRI. Invest Ophthalmol Vis Sci 2017; 58:4390–4398. [PMID: 28813574 PMCID: PMC5559179 DOI: 10.1167/iovs.17-21861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose The eye and its accessory structures, the optic nerve and the extraocular muscles, form a complex dynamic system. In vivo magnetic resonance imaging (MRI) of this system in motion can have substantial benefits in understanding oculomotor functioning in health and disease, but has been restricted to date to imaging of static gazes only. The purpose of this work was to develop a technique to image the eye and its accessory visual structures in motion. Methods Dynamic imaging of the eye was developed on a 3-Tesla MRI scanner, based on a golden angle radial sequence that allows freely selectable frame-rate and temporal-span image reconstructions from the same acquired data set. Retrospective image reconstructions at a chosen frame rate of 57 ms per image yielded high-quality in vivo movies of various eye motion tasks performed in the scanner. Motion analysis was performed for a left-right version task where motion paths, lengths, and strains/globe angle of the medial and lateral extraocular muscles and the optic nerves were estimated. Results Offline image reconstructions resulted in dynamic images of bilateral visual structures of healthy adults in only ∼15-s imaging time. Qualitative and quantitative analyses of the motion enabled estimation of trajectories, lengths, and strains on the optic nerves and extraocular muscles at very high frame rates of ∼18 frames/s. Conclusions This work presents an MRI technique that enables high-frame-rate dynamic imaging of the eyes and orbital structures. The presented sequence has the potential to be used in furthering the understanding of oculomotor mechanics in vivo, both in health and disease.
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Affiliation(s)
- Saikat Sengupta
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - David S Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Alex K Smith
- The Centre for Functional MRI of the Brain, The University of Oxford, Oxford, United Kingdom
| | - E Brian Welch
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States
| | - Seth A Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States
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